Alternative fitness models with the same allele frequency dynamics

Area of Science:

• Population genetics
• Evolutionary genetics
• Quantitative genetics

Background:

• Genotypic fitness determines allele and haplotype frequency changes in populations.
• Understanding fitness is crucial for predicting evolutionary trajectories.
• Current models often assume specific fitness landscapes.

Purpose of the Study:

• To investigate the identifiability of genotypic fitness models.
• To determine if allele or haplotype frequency data can uniquely identify fitness sets.
• To explore the implications of alternative fitness models.

Main Methods:

• Analysis of one- and two-locus genotypic fitness equations.
• Examination of allele and haplotype frequency dynamics.
• Development of a procedure to generate alternative fitness sets under specific conditions (single locus, two loci with linkage equilibrium).

Main Results:

• Identified that multiple, distinct genotypic fitness sets can yield the same allele or haplotype frequency dynamics.
• Demonstrated that allele or haplotype frequency trajectories and equilibrium distributions are insufficient to distinguish between these alternative fitness models.
• A method was developed to generate some alternative fitness sets for specific genetic scenarios.

Conclusions:

• Genotypic fitness models are not uniquely identifiable from population frequency data.
• Frequency-dependent fitness models can be particularly ambiguous.
• Careful consideration of model assumptions is necessary when interpreting evolutionary genetic data.